Burn in hell?

Well, unless you're into things like "the committee are
meeting" or "that band play really well" where
you get agreement by sense instead of by formal concord. 

It's called synesis. The KJV translators routinely used
"wages" with singular agreement.

Then again, we still have people struggling with the idea of
"singular they" and "impersonal you," both
of which were perfectly grammatical for Chaucer, for
Shakespeare, for Dickens, and even for current writers. But
not prescriptivists of nearly any stripe.

Russian has a ton of this kind of problem, where they show
gender on adjectives and past tense verbs: So "The good
doctor I saw yesterday studied in Saint Petersburg"
should have a masculine verb, but if the doctor's a she most
Russians will use a feminine verb. Almost all, but not all,
will use a masculine adjective ("good"), but if the
sentence is something like "The good doctor I saw
yesterday is pregnant" you're more likely to get a
feminine adjective as well. It's considered not so great to
use a feminine word for "doctor", but that solves
the problem. Prescriptivists have a nightmare and bemoan the
lack of proper "culture of speech," convinced that
the language of Pushkin and Tolstoy is best maintained by
ignoring how Pushkin and Tolstoy actually spoke and returning
to a hypothetical, ahistorical kind of linguistic purity. So
it's not an English-specific kind of intellectual conceit.

You also miss the strict parallelism and the fact that
thanatos and zoe might well be taken to have the same
modifier, aionios, since it agrees equally well with both and
the parallelism wouldn't be lost on the people reading Paul.
You lose that parallelism in English, I think.

τα  γαρ  
οψωνια  
  της    
αμαρτιας
θανατος

the for   provisions of-the  of-sin   death 

το  δε   
χαρισμα
   του    
θεου    
ζωη 
the but   gift       of-the  of-god   life 

αιωνιος
εν
χριστω
ιησου
τω
κυριω
ημων
eternal in Christ Jesus the lord our

"Provisions" or "provisions-money" is the
more usual translation outside the NT for
"opsonion". It's a metaphorical usage here.
"Gar" and "de" are clitics (nothing
obscene there, sorry) in case you're wondering about why the
conjunctions are placed after the definite articles
"ta" and "to".

Nonetheless, I guess you do have a kind of a point, although
try as I might I don't really see the logic: "But since
everyone dies, it seems to be an impossibility." I'm not
sure why it's an impossibility--everybody dies, and the theory
is that it's because everybody's sinned (well, with one
exception, and he allegedly agreed to die). I'm not sure
unfalsifiable hypotheses are generally considered impossible.
The problem is that the consequences, the conclusion, tends to
be universally true while the premise is unverifiable. To show
it's an impossibility I guess a first step would be to find an
immortal sinner. Good luck with that one. Although that would
knock the "All men are mortal; Socrates is a man"
start to the traditional syllogism right in the head.